curl --request POST \
  --url https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "arc_getCertificate",
  "params": [
    55000000
  ]
}
'

import requests

url = "https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/"

payload = {
    "id": 1,
    "jsonrpc": "2.0",
    "method": "arc_getCertificate",
    "params": [55000000]
}
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({id: 1, jsonrpc: '2.0', method: 'arc_getCertificate', params: [55000000]})
};

fetch('https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'id' => 1,
    'jsonrpc' => '2.0',
    'method' => 'arc_getCertificate',
    'params' => [
        55000000
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/"

	payload := strings.NewReader("{\n  \"id\": 1,\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"arc_getCertificate\",\n  \"params\": [\n    55000000\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/")
  .header("Content-Type", "application/json")
  .body("{\n  \"id\": 1,\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"arc_getCertificate\",\n  \"params\": [\n    55000000\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n  \"id\": 1,\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"arc_getCertificate\",\n  \"params\": [\n    55000000\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "height": 55000000,
    "round": 0,
    "block_hash": "0x9a9ecf9348af3c128d63dcb4555b4586b9e9a503c67220029602a93aed14c76e",
    "signatures": [
      {
        "address": "0x2012459eddb529fcd8429ba73006a6340ff05232",
        "signature": "P3GaOsv6kJE9IyJtaBBjFvebQtAEttCGKalkwbk9VeVy7GxK1l3S/GhATET24iKbyY8SDmwvVMQjPaDOCz+nAQ=="
      },
      {
        "address": "0x66a99d2834cf369d900de5da88ad2944ccb12e70",
        "signature": "+UX4HW+dJaI0nAKB+3Ah3g6iR31jAYx62wFbufrNE7zttMYYaz6NBtXNX8Zc3kDaEWEO2T+IldaD927I865FCw=="
      },
      {
        "address": "0xfeb2b98d614701434ea6a12ccf29e0e40ae56941",
        "signature": "6C3dyx4Yoy1tU/sIKEGmcYWw7MGal2mZfFcLbz2qTQ7dfDvSC/Jq4vW3lVWRu7tzWMbmEcezAyw5bHABloKtAA=="
      },
      {
        "address": "0x602930d1ab44f1744f42e842b701c2b149c5da4f",
        "signature": "BDWeBNMhNypstuQwLlSbcQhjZVShr6F4K9d8Q4AG2PpRgFC9xoLDS+rrhPpUlZBi8EGZj3bR2dHntcjPv/rDAg=="
      },
      {
        "address": "0x6689a18548c978619d7c11698244eed76ae10856",
        "signature": "ZUOgt73xJ0gIBwshzPWguvNdMA8aWLDZS+PAmR4df17SJNsBciXfNCGHiFzlzQnUmPTlpLDHqhDH/51AG6BEBA=="
      },
      {
        "address": "0x2e78053671f707844a631bc907d4855894848fe3",
        "signature": "dcICOyPk2uBf+b0V02nVbE7qpy8LlUMo8NJOVKBz8NplXvViiPy8zPDFePloF20aJbiI52MfQ2DTDBZcaoHdAQ=="
      },
      {
        "address": "0x6791e002c8419e8a2fa5266e2951ed1780bc2295",
        "signature": "4JiWLZYCMVQkNVpj4E30m5UjOT/U6jTajr5CYrH9DgAxCEMhhBeYWk5Jiztw+A7qHNBH77qmHyybnjkl7MZFDw=="
      },
      {
        "address": "0xa3616c3a52e49facf1a0d59316dc87ce471e8129",
        "signature": "Ya45YNsjB9wuTY2RF/uHC+HSShGyXx6MR0SKYbc6crYYPp9hSE9G5RJo2pKADtKuAK3VDf5NnYnHiRFgIDWPAA=="
      },
      {
        "address": "0x6ea7bc8812a8837a861f4ca7acd83bca1684626a",
        "signature": "qz2RqUT5ZXN/QZVi0TJFS3qOHizWW9LBo+oCkg3COSo3JryURmVk2u3R1qSw5rxrxnPi81yCGamN0ccjE4IQAg=="
      },
      {
        "address": "0x643ad8ec952efa7d3060dcf94b92e9eba7baab19",
        "signature": "POIY1dMaCOP7uMksphmJjdp3XtU6ieKufBkDr/rflJAaOHhr/5RVnH6MZN3Z/UUBwnTtNRDbhmx+X98MU+IzAQ=="
      },
      {
        "address": "0x424ca01b5a849b7ce2e6e4d92a0443ce81f16fd2",
        "signature": "rgCm91C5n723hNuqj6oDd4Wf3yS3SsQloUoinWWzw7+7vKeBTbzUc1UbzFkc62rpZdoDjMOuihx+rTA21/OWDA=="
      },
      {
        "address": "0x68960d463d8a51095947a416fdb7973a87f675d0",
        "signature": "XNxfZUxxH8Ak6rSwDw9AoA7LVQWtBwnlcv4iWMz4rl3oCFhBPOu8drCi/tGQE3BhDNftJlBRdYZs2kZeeK+lCw=="
      },
      {
        "address": "0xfdc37d533f82159bf6c46da00db4faa379b941de",
        "signature": "/X2EWeitrkHQg/ubV36qk2fwaL3JrcCo954J/VEJqPqkdZIOCpnjx9GF9FS6WELApBmjhdkeV2zgJjH+Bd7OBQ=="
      },
      {
        "address": "0x7e4499718f868ff1f89fe5432e11c9f9f3e01fae",
        "signature": "82lZYmRk3duR1yUZIHi5QS1/BZEAHS6fg6t7a7EhwjRLf7/lSLH7iLaLZN46SiSNMiVIXS7hf/k/LCv9Grt4BQ=="
      }
    ]
  }
}